!zspawn Problem

I need it to allow players to use !zspawn to spawn late into the game (dependant on mother zombie) and have the ability to use !zspawn after they die as a zombie or human (suicide).

Currently players that join late into the game, always respawn as a human even after the mother zombie has spawned. I want them to respawn as a human before a mother zombie spawn, and a zombie after the mother zombie has spawned.

Also I cnt figure out how to let players use !zspawn when they die, it just gives me a message in chat saying:

ZSpawn can only be used if you joined late during a round in progress.